title: Prenatal diagnosis of β-thalassemia in twin pregnancies in Iran.
abstract: OBJECTIVE
  Prenatal diagnosis of β-thalassemia carrier couples has helped to prevent bearing affected children. Among 177 couples referred to our laboratory for prenatal diagnosis, 14 mothers had twin pregnancies.
  
  
  METHODS
  By using direct and indirect methods, we determined their mutations and linkage analysis using polymorphic markers (restriction fragment length polymorphism [RFLP]).
  
  
  RESULTS
  It was shown that in five families both fetuses were heterozygote carriers. In another five families, one fetus was normal and the other one was carrier. In two families, one fetus was affected and the other one was heterozygous carrier; in one case one fetus was affected and the other one was homozygote normal. In the last family both fetuses were homozygote normal. If all fetuses were fraternal then one would expect to see seven homozygote normal and the same number affected, and 14 carriers.
  
  
  CONCLUSIONS
  Our results indicated that at least in cases where both fetuses had identical genotypes, then they may be identical twins. Molecular testing indeed showed that in three cases the twins were identical. Another point is that in three cases, one of the twin fetuses was affected and the other one was either normal or heterozygote in which only the affected fetuses were aborted by the specialist.
authors.affiliation: Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.zeinalipasteur@yahoo.com.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Kainimoghaddam
authors.forename: Atefeh
authors.initials: A
authors.lastname: Valaei
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Bayat
authors.forename: Maryam
authors.initials: M
authors.lastname: Taghavi Basmanj
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Navabmoghaddam
authors.forename: Marjanalsadat
authors.initials: M
authors.lastname: Mortezazadeh
authors.forename: Ladan
authors.initials: L
authors.lastname: Teimoori-Toolabi
authors.forename: Setareh
authors.initials: S
authors.lastname: Ahmadi
authors.forename: Shaghayegh
authors.initials: S
authors.lastname: Sadegh
authors.forename: Alireza
authors.initials: A
authors.lastname: Kordafshari
authors.forename: Morteza
authors.initials: M
authors.lastname: Karimipoor
authors.forename: Sirous
authors.initials: S
authors.lastname: Zeinali
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D012150:Polymorphism, Restriction Fragment Length; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D017086:beta-Thalassemia / Q000175:diagnosis*